Abrasive material and method of making it.



UNITED STATES PATENT onrron LEWIS E. SAUNDERS, or NIAGARA FAlLl'iS, newYORKyASSIGNbR To NORTON COMPANY,

or wonons'rnn, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.-

ABRASIVE MATERIAL AND METHOD OF MAKING IT.

No Drawing.

To all whom it may concern: 7

Be it known that I, LEWIS E. SAUnDnns, a citizen of the United States,residing at Niagara Falls, in the county of Niagara and State of NewYork, have invented certain new and useful Improvements in AbrasiveMaterial and Method of Making It, of which the following is aspecification.

This invention relates to the preparation in the electric furnace of analuminous ma-- terial adapted for use as an'abrasive, and possessingcertain novel distinguishing characteristics and properties ashereinafter set forth.

In the preparation in the electric furnace of abrasive materialsconsisting largely of alumina, it has been customary to calcine bauxiteto expel the water of hydration, and thereafter to fuse the material inan electric furnace between carbon electrodes, usually with the additionto the charge of small proportions of carbon added for the purpose ofreducing the oxids of iron, silicon and titanium. The resulting productvaries widely in color, usually of various shades of red, brown or gray,and contains varying proportions of iron, silicon, titanium and calcium.As above pointed out it is produced under reducing conditions. 1 I havediscovered that under certain conditions as hereinafter described I amenabled to produce in the electric furnace a material in certain whichis blue or blue-black in color although of varying shades, whichexhibits a strong tendency to crystallization and possesses qualitiesadapting it for use as an abrasive particular relations. To prepare thismaterial I may proceed as follows: Commercial bauxite containing bothiron and titanium is ground and calcined, and is thereafter melted in asuitable electric furnaoe with precautions to avoid strongly re- U S.Patent No. 775,654, issue ducing conditions; that is to say, no carbonis added'to the charge, and the charge is referably melted as rapidly aspracticable etween graphite electrodes.

The furnace may beoof the ty e. shown in d November 22,1904, to A. C.Higgins.

If iron and titanium be present as oxidized compounds and in properproportions the product will be found to be blue or blueblack in colorand to possess the properties and characteristics hereinafter set forth.

It is essential to the production of an Specification of Letters Patent.Application filed December 26, 1908. Serial No. 469,309.

abrasive having the desired qualities that the iron should be present inexcess of the titanium, and it is preferable that the per centage byweight of iron oxid should be 4 I at least double that of the titaniumoxid, although 1t may very considerably exceed tlns proportion.

Patented A r 12, 1910.

Without restricting the;

invention to the proportions therein indicated, I give thefollowing'analysis-of a blue-black aluminous abrasive possessing all ofth; desirable characteristics below mentione TlO' v 3. 10 Fe O 12.04. IS10 1.10 Y CaO 0. s9

The absolute percentage of iron-and titanium oxids depends upon theshade ofcolor desired and also upon the percentage of s1l1ca,th epercentage of iron and titanium necessary to produce a given shadeincreasmg with the percentage of silica. It is ad visable thereforeto'select a bauxite low in silica in order that the proportions of ironand titanium maynot be excessive or sufficient to affect undesirably theabrasive qualitiesof the product. If the material be substantially freefrom silicon the titanium oxid may be as lowas' 1 to 2 per cent., theiron oxid being at least 2 to 4:

per cent. If silica be present in substantial proportions an increase-inthe per cent. oftitanium oxid and iron oxid isnecessary, theseincreasing preferably in approximately the proportion of two parts ofiron oxid to one part of titanium oxid, and the amount,

of increase depending on the proportion of silica present. For example,with 4' per cent. of silica a compound having-the de sired propertiesmaycontain 4.5 per cent.

of titanium oxid and 9 per cent. of iron;-

or with 8 per cent. of silica the mixture may contain 6 to 8 per cent.of titanium oxid and 12 to 20 per cent. of iron 'oxid. In

general, is is difiicult or impossible to obtain a suitable materialwith silica in excess of 8 per cent.

Proper proportions of iron and titaniummay be secured by IIllXlIlg1ron-ore or mill scale with bauxite deficient in iron, or byv 110 mixingdifierent grades of bauxite in proper I of titanium OXHl, and from Q-to20 per cent. case the bauxite is deficient in titanium, this 3proportions as indicated by analysis. In

may be added in the form of titaniferous bauxite or other titanium oresor compounds.

The material produced as above described is taken from the furnace inthe form of pigs or masses having the characteristic blue or blue-blackcolor and exhibiting a decided tendency to crystallization, transparentplate-like crystals of clear blue color exceeding two centimeters inlength being found at times in cavities of the mass. The crushed andgraded abrasive is found to possess superior holding qualities for glueor other adhesives, and is therefore particularly adapted for thepreparation of abrasive paper or cloth; it is also particularly suitedin the qualities of temper and hardness to the class of work to whichabrasive paper or cloth is applied, as for example finishing leather,and certain classes of metal work, more particularly disk grinding.

As a robable explanation of the develop ment of the blue or blue-blackcolor under the conditions specified, it may be pointed out that thecompound Fe TiO is violet, and may perhaps be formed in the molten massand impart its color thereto.

I claim I 1. The herein described electric furnace product, comprising apreviously molten mixture containing upward of 60 per cent.

oi. oxid of aluminum, from 1 to 8 per cent.

' oi iron oxid, the oxids of iron and titanium being present in theproportion and amount required to produce a lustrous product having ablue or blue-black color.

The herein described electric furnace product. comprising a previouslymolten mixture containing upward of per cent. of oxid of aluminum, from1 to per cent. of titanium oxid, and from to 20 per cent. of iron oxid,the oxid of iron being in approximately twice the proportion by weightof the titanium oxid, and the oxids of iron and titanium being presentin the amount required to impart a blue or blue-l'ilaclt color to themass. V r

3. The method of preparing a material suitable for use as an abrasive,which consists in melting in an electric furnace a mixture containingupward of per cent. of oxid oi aluminum, from 1 to 8 per cent. oftitanium oxid, and from 2 to 20 per cent. of iron oxid, the oxids ofiron and titanium required to impart a blue or blue-black color to themass.

In testimony whereof I a'llix my signature in presence of two witnesses.

v LEWIS E. SAUNDERS.

Witnesses:

R. P. CAPRUN,

Hnxnx Dncmvoa'rir.

being present in the proportion and amount

